Rubbing-strip for centrifugal air-compressors.



R. H. RICE.

RUBBING STRIP FOR CENTRiFUGAL MR COMPRESSORS.

APPUCATION r|L0 AUGIH. 19x4.

1 1 59,095. atented Nov. 2,1915.

Fig. l.

Witnesses:

Inventor Rih d H.Rice,

b fzil rfim aqtg.

UNITED STATES PATENT OFFICE.

RICHARD H. RICE, F LYNN. MASSACHUSETTS. ASSIGNOB. T0 GENERAL ELECTRIC comm, A CORPORATION 01? NEW YORK.

Specification of Letters Patent.

Patented Nov. 2, 1915.

Application filed August 31. 1914. Serial No. 859.330.

To all whom it may concern:

Be it known that I, RICHARD H. Ric's, a citizen of the United States, residing at Lynn, county of State of hiassachu' settsha e inrented certain new and useful Improvements in Rubbing-Strips for Centrifugal Air-Compressors of which the following is a specification.

This invention relates to centrifugal machines for compre 'ing air, and its object is to provide renewable edges for the impeller vanes. permitting them to be replaced in case they become injured by contact with the walls of the casing in which the impeller rotates.

The running clearance between the impeller and the casing is usually made small in order to avoid losses by leakage. If, by reason of accidental misadjnstment of the position of the impeller shaft, the edges of the ranes come in contact with the wall of the casing. the renewable edges which I provide. wear ofi' readily without causing vi bration of the shaft or damage to any part.

In a previous application, filed August 13th. W12, Serial Number 715,709, I have disclosed a removable edge for impeller ranes, consisting of a strip of soft metal secured to the edge of the vane, which actual use has proved to be an efiicient and valuable improremeut.

My present inrention has particular ref crence to a new mode of securing the rubhing or wear strip to the impeller vane, whereby a more substantial and secure fastcninzofthesestripsisefi'ected. Thisis desirable not only on account of the rub in action but also because of the centriiu force exerted upon them. This new method does not depend entirely upon rivets for fastening the strips to the impeller blade, since the strip itself is interwoven or laced into the edge of the impeller blade In or der to avoid any sacrifice of strength and yet to afiord a better resistance to the centrifugal and rubbin strains to which the strip is subjected, I ma the strip in zigzag form and let it into slots cut in the edge of the vane, :0 that it lies alternately on opposite sid8 thereof.

In the accompanying drawing, Figure 1 is an axial section of a portion of a centrifugal air compressor showing an impeller rovided with my improved rubbing strip. zg.2isanedgeview of twoofthevanes so equipped. Fig. 3 is a perspective view of one of the strips, and Fig. 4 is an end view of the entire compressor.

The casing 1 or the compresor has the usual intake 2 and outlet 3, with one or more hollow walled diaphragms 4 forming chambers in which the impellers 5 can rotate. A shaft- 6 pasing centrally through the easing carries the several impellers with which a multi-mge machine is provided. Each impeller has a central web 7 supporting vanes 8 on each side of it. The air enters the impeller atthe center and is thrown oil through stationary discharge vanes. The vanes are preferably radial, at least throughout their outer portions 10, and along each edge of this portion is secured the rubbing strip. This is a stra ht piece of thin soft. metal, such as brassfhabbitt or other suitable alloy, bent into a zigzag shape and preferablv having longitudinal sections 11 lying alternately on opposite sides of a median plane and connected by short transverse sections 12, whose length is equal to the thickness of the vane. blots 13 are sawed in the edge of the vane at the same distance apart as the transverse sections 12 of the rip and of a depth a little less than the width of the strip, so that the strip projects a little beyond the vane. After the strip has been slipped into the slots, a few rivets 14 are put in to keep it in place. But the centrifugal strains tending to throw the strip outwardly are entirely sustained by the of theslots engag'ng the transverse sections 12 of the strip, while the rubbing strains, if any, are sustained by the portions of the vanes underlying the longitudinal sections 11 on the front of the vane and against which said sections are held in close contact. The alternate sections 11 on the back of the vane transmit the rubbing rains to the vane through the transverse sections 12 and the rivets 14.

The invention therefore provides a strong yet simple mode of securing a rubbing girip to an impeller vane, which affords ample resistance both to centrifugal and rubbing strains.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatus shown is only illustrative, and that the in ention can be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1- The combination in a centrifugal compreor having a casing and an open sided impeller with vanes designed to run with close clearances, of a wear strip fixed to and projecting over the edges of the vanes into clcse roximity to the casing wall, said we r strips each comprising a zig-zag strip lying alternately on opposite sids of aid vanes.

'3. The combination in a centrifugal oomprmor having a and an open sided impeller withvanesdesignedtorunwith close clearances, of a wear strip fixed to and projecting over the edges of the vanes into clcse proximity to the casing wall, said wear strips each comprising a zig-zag strip let into the edges of the vanes.

3.1nacentrifugaloomptmorhavinga casing and an open sided impeller having vanes designed to run with close clearances, the combination with the vanes having slots in their edges of wear strips fixed to and P 'OjQCting over the edges of the vanes with transverse portion received in said slcts 4. In a centrifugal compreor having a casing and an open sided impeller having ma designed to run with close clearances the combination with the vanes having slots in their edges of wear strips which project over the of the vanes into close proxto time wall and are woven back and forth in said slots so as to lie on alter nate sides of the vanes.

In Witness whereof, I have hereunto set my hand this 28th day of August 1914.

RICHARD H- RICE Witnesses:

JOHK A. Mchlasns, Jr., Roam Smn.

cqaicsofthispatzntmbeobtainedtortveceptsmbythe Comjssiolerofhtcnts. washingtomnc.

Correctlons in Letters Patent No. 1,159,095

It is hereby certified that in Letters Patent No. 1,159,095, granted Nove1nher 2, i915, upon lire application of Richard H. Rice, of Lynn, Massachusetts,

for an improvement in Rubbing-Strips or Centrifugal Air-Compressors," errors a war in the winter] 5 mcificntion re uirin correction as follow: Pa 0 1, line 69 P] i I q g P g r after the word v;m -s" insert the reference-numeral 9; same page, line 70, after the word vanes ineert the refererice-numeral 8; and that the said Letters Patent should he read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 7th day of December, A. D., 1915.

[SEAL] R. F. WHITEHEAD,

Acting Commissioner of Patents. C1. 230-1L 

